Distance Learning Module: Weather, Weather Everywhere: Part II (Other Planets)
What causes weather, how do we study it, and what is the weather like on other planets?
Learn all about it in this two-part series, geared toward middle-school learners! Start with Part I to become familiar with weather terms & concepts and how they apply to Earth, before moving on to this section.
in this stunning new view of Jupiter's atmosphere, as seen from NASA's Juno spacecraft, we can actually see two storms merging (joining together). Look for the two white ovals within an orange band, just to the left of center. These storms are anticyclonic—meaning they rotate counter-clockwise. They may be merging because of disturbances in the atmosphere from oval ba (the large white circle just above the two merging storms). Oval BA is the second largest anticyclonic storm in Jupiter's atmosphere, second only to the Great Red Spot. Image credit: NASA/JPL-Caltech/SwRI/MSSS
Let’s Review.
In Part I, we learned that:
WEATHER refers to conditions in the atmosphere—the layer of gas that surrounds a planet like an “envelope”
Weather occurs in a specific area and lasts for a short time
A storm is a severe weather event, usually involving heavy wind and precipitation
There are several factors that affect a planet’s weather:
the tilt of the planet's axis
the shape of its orbit around the sun
its atmosphere
its average distance from the Sun
the length of its day
With that in mind, let’s take a look at the extreme weather conditions on some of the other planets in our solar system…
Image credit: NASA/Lunar and Planetary Institute
Neptune
Image Credit: NASA / JPL / Voyager-ISS / Justin Cowart
Neptune, the eighth and farthest true planet in our solar system, is an average of 2.8 billion miles (4.5 billion km) from the Sun. That means its temperature is extremely cold: below -350 degrees F (-200 degrees C) on average. Brrrrrrrrr!
Neptune is so far away from the Sun that even daylight is very dim there—900 times less bright than sunlight on Earth. It has a thick atmosphere of methane and ammonia, and has experienced the fastest wind speeds ever detected in the solar system, at 1,500 miles (2,400 kilometers) per hour.
Neptune is tilted on its axis at a similar angle to Mars and Earth, so it experiences seasons…but a Neptune year is so long, each season lasts 40 years!
Image credit: NASA/JPL-Caltech
Uranus
Like its neighbor Neptune, this planet is an ice giant. At an average of 1.8 billion miles (2.9 billion km) from the Sun, Uranus is extremely cold and windy. In fact, it’s one of the coldest planets in the solar system. It experiences huge storms—some as big as 1/2 to 2/3 the size of the United States! It has clouds made of ammonia and methane ice crystals.
Uranus’ axis is tilted at an extreme 98 degree angle. This means it rotates in a direction perpendicular to its Equator (north-south versus east-west)—its movement looks like a ball rolling down a hill, rather than a spinning basketball balanced on a fingertip.
Since Uranus is so far away from the Sun, it takes about 84 Earth years to make a single orbit. And its extreme tilt means large parts of the planet see nothing but daytime or nighttime for an entire season—which lasts 21 Earth years!
Jupiter
Jupiter (482 million miles from the Sun) has no solid ground like we do on Earth. This planet is a gas giant, meaning it is primarily made of gas. A liquid ocean of hydrogen surrounds its small, hot, rocky core, and the large atmosphere consists mostly of hydrogen and helium. The entire planet is covered in bands of swirling ammonia ice clouds, blowing in alternating directions: if one band is blowing from east to west, the ones to either side of it are blowing from west to east.
Jupiter has an axial tilt of only 3 degrees, so while it technically experiences seasons (which last about three years each), the weather does not change seasonally. However, its dense, turbulent atmosphere can cause dramatic storm activity. The most famous storm on Jupiter is the Great Red Spot: a gigantic hurricane twice the size of Earth, which has been raging in the atmosphere for at least 150 years (and perhaps much longer)!
Mars
Mars (141 million miles from the Sun) has a thin atmosphere of primarily carbon dioxide. As solar radiation warms the Martian atmosphere, it causes air to begin moving. Remember, we learned in the last module that warm air rises. When this happens on the surface of Mars, warm air near the ground lifts extremely fine grains of dust up with it. Dust storms as big as continents can swirl through the Martian atmosphere for months at a time! On Earth, dust storms tend to end relatively quickly as water condenses on the grains of sand. The dry environment of Mars—the lack of water vapor in the air—is what allows these dust storms to last so long.
Mars’ thin atmosphere also does not trap much of the Sun’s heat near the surface of the planet. Temperatures vary greatly with the seasons, at the poles, and even throughout the day. The average temperature on Mars is about -81 degrees F: however, temperatures may reach levels as low as -220 degrees F in the wintertime at the poles or as warm as +70 degrees F toward the equator in the summer.
Venus
Venus is the second-closest planet to our Sun, at a distance of 68 million miles (107 million km). It is covered by a thick atmosphere of carbon dioxide, and has clouds made of sulfuric acid. Venus’ atmosphere traps heat from the Sun, warming the surface of the planet: a process known as the greenhouse effect. This is why Venus is the solar system’s hottest planet, even though Mercury is closer to the Sun. Venus’ average temperature is a sizzling 864 degrees Fahrenheit (462 degrees Celsius)—that’s hot enough to melt lead! If this planet ever had oceans, they have long since evaporated.
One extremely unusual thing about Venus is that it has a rapid orbit around the Sun (due to being relatively close-by), but it rotates extremely slowly on its axis. This means that Venus revolves around the Sun every 225 Earth days, but its rotation takes 243 Earth days: a day on Venus is slightly longer than a year! Venus also rotates clockwise—the opposite direction of all the other planets in our solar system.
Mercury
Mercury is the only planet in the solar system not to be surrounded by a substantial atmosphere. It has a small mass and a weak gravitational field, so atoms from its atmosphere are constantly floating away and becoming lost in outer space. Mercury’s extremely thin atmosphere of oxygen, sodium, and hydrogen does little to protect its surface from solar radiation. At a distance of 36 million miles, Mercury is also the closest planet in the solar system to our Sun.
Due to the precarious atmosphere, Mercury has no real weather: it does not experience storms, precipitation, or big fluctuations in atmospheric pressure. However, it does undergo the greatest shift in temperature between daytime and nighttime (diurnal temperature spread) of any planet in our solar system. Days might get as hot as 750 to 800 degrees F (399 to 427 degrees C), while the nighttime temperature can plummet nearly one thousand degrees to -330 degrees F (-166 degrees C). In addition, since Mercury has virtually no atmosphere to scatter light, the sky would appear black, even though the Sun's disk itself would be over twice as large as what we observe from the Earth.
Conclude and Reflect
Knowing what you now know about weather on other planets, which place do you think would be the most UNPLEASANT place to live or visit? Do any of these extreme planetary weather events sound like something you’d WANT to experience? Why?
On which of these planets could you land a probe? Why? What makes this an impossible task on the other planets?
List FIVE types of weather on other planets that are like Earth weather. List FIVE other types of weather events that happen on other planets but do not happen on Earth.
